Improving Split Reporters of Protein-Protein Interactions through Orthology-Based Protein Engineering

Protein-protein interactions (PPIs) can be detected through selective complementation of split fluorescent reporters made of two complementary fragments that reassemble into a functional fluorescent reporter when in close proximity. We previously introduced splitFAST, a chemogenetic PPI reporter with rapid and reversible complementation. Here, we present the engineering of splitFAST2, an improved reporter displaying higher brightness, lower self-complementation, and higher dynamic range for optimal monitoring of PPI using an original protein engineering strategy that exploits proteins with orthology relationships. Our study allowed the identification of a system with improved properties and enabled a better understanding of the molecular features controlling the complementation properties. Because of the rapidity and reversibility of its complementation, its low self-complementation, high dynamic range, and improved brightness, splitFAST2 is well suited to study PPI with high spatial and temporal resolution, opening great prospects to decipher the role of PPI in various biological contexts.

Engineering of Tunable Allosteric-like Fluorogenic Protein Sensors

Optical protein sensors that enable detection of relevant biomolecules of interest play central roles in biological research. Coupling fluorescent reporters with protein sensing units has enabled the development of a wide range of biosensors that recognize analytes with high selectivity. In these sensors, analyte recognition induces a conformational change in the protein sensing unit that can modulate the optical signal of the fluorescent reporter. Here, we explore various designs for the creation of tunable allosteric-like fluorogenic protein sensors through incorporation of sensing protein units within the chemogenetic fluorescence-activating and absorption-shifting tag (FAST) that selectively binds and stabilizes the fluorescent state of 4-hydroxybenzylidene rhodanine (HBR) analogs. Conformational coupling allowed us to design analyte-responsive optical protein sensors through allosteric-like modulation of fluorogen binding.

Vaccination acceptability in the French general population and related determinants, 2000-2021

BACKGROUND

This study describes the evolution of vaccination acceptability and associated determinants in the French general population between 2000 and 2021, and vaccinations with the highest vaccine hesitancy between 2010 and 2021.

METHODS

Data were collected from the nine national 'Health Barometer' cross-sectional surveys conducted between 2000 and 2021. These surveys included French-speaking individuals aged 18-75 years old who were selected through randomly generated landline and mobile phone numbers. Participants were asked about their acceptability of vaccination in general and their vaccine hesitancy toward any particular vaccinations. Determinants of vaccination acceptability were studied using univariate and multivariate Poisson regressions.

RESULTS

The proportion of persons who found vaccination acceptable in general (i.e., answering "very" or "somewhat" favourable in the survey interview) decreased from 91.1% in 2000 to 61.2% in 2010 (the latter year coinciding with the 2009 H1N1 influenza pandemic), increased in 2014 (78.8%), slightly fluctuated until 2019 (74.2%), and increased again in both 2020 (80.0%) and 2021 (82.5%) during the COVID-19 pandemic. Irrespective of the year, acceptability was higher among persons with higher incomes, those with a higher education level, and individuals not living alone. In 2021, for the first time, vaccination acceptability was higher among persons over 44 years old (versus 18-24 year-olds) and among retired persons (versus workers). The highest hesitancy rate for a vaccine was for the 2009 H1N1 influenza virus in 2010 (41% answering "somewhat" or "very" unfavourable). In 2021, the highest rate was for the COVID-19 vaccine (21%).

DISCUSSION

Unlike the experience of the 2009 AH1N1 influenza pandemic, which led to a collapse in vaccination acceptability among the French general population, acceptability continued to increase during the COVID-19 pandemic. However, the pre-2010 level was not reached. Our results show a tendency towards a widening social and economic gap in terms of vaccine acceptability over time.

A fluorogenic chemically induced dimerization technology for controlling, imaging and sensing protein proximity

Molecular tools enabling the control and observation of the proximity of proteins are essential for studying the functional role of physical distance between two proteins. Here we present CATCHFIRE (chemically assisted tethering of chimera by fluorogenic-induced recognition), a chemically induced proximity technology with intrinsic fluorescence imaging and sensing capabilities. CATCHFIRE relies on genetic fusion to small dimerizing domains that interact upon addition of fluorogenic inducers of proximity that fluoresce upon formation of the ternary assembly, allowing real-time monitoring of the chemically induced proximity. CATCHFIRE is rapid and fully reversible and allows the control and tracking of protein localization, protein trafficking, organelle transport and cellular processes, opening new avenues for studying or controlling biological processes with high spatiotemporal resolution. Its fluorogenic nature allows the design of a new class of biosensors for the study of processes such as signal transduction and apoptosis.

A fluorescent reporter system for anaerobic thermophiles

Owing to their inherent capacity to make invisible biological processes visible and quantifiable, fluorescent reporter systems have numerous applications in biotechnology. For classical fluorescent protein systems (i.e., GFP and derivatives), chromophore maturation is O₂-dependent, restricting their applications to aerobic organisms. In this work, we pioneered the use of the oxygen-independent system FAST (Fluorescence Activating and absorption Shifting tag) in the thermophilic anaerobe Thermoanaerobacter kivui. We developed a modular cloning system that was used to easily clone a library of FAST expression cassettes in an E. coli-Thermoanaerobacter shuttle plasmid. FAST-mediated fluorescence was then assessed in vivo in T. kivui, and we observed bright green and red fluorescence for cells grown at 55°C. Next, we took advantage of this functional reporter system to characterize a set of homologous and heterologous promoters by quantifying gene expression, expanding the T. kivui genetic toolbox. Low fluorescence at 66°C (T_opt for T. kivui) was subsequently investigated at the single-cell level using flow cytometry and attributed to plasmid instability at higher temperatures. Adaptive laboratory evolution circumvented this issue and drastically enhanced fluorescence at 66°C. Whole plasmid sequencing revealed the evolved strain carried functional plasmids truncated at the Gram-positive origin of replication, that could however not be linked to the increased fluorescence displayed by the evolved strain. Collectively, our work demonstrates the applicability of the FAST fluorescent reporter systems to T. kivui, paving the way for further applications in thermophilic anaerobes.

Cage-like structures based on constrained cyclic arylopeptoids

The access to cupola-like or tube-like structures from ortho- and meta-arylopeptoid macrocycles was explored through CuAAC reaction using a partially flexible bis(azide) and Cu^I-N-heterocyclic carbene as catalyst. NMR studies showed that a bis-triazolium bicylic compound in the ortho-series adopts well-defined structure in polar aprotic and protic solvents. Besides, preliminary study revealed its potential for oxoanion recognition.

Genetic Targeting of Solvatochromic Dyes for Probing Nanoscale Environments of Proteins in Organelles

A variety of protein tags are available for genetically encoded protein labeling, which allow their precise localization and tracking inside the cells. A new dimension in protein imaging can be offered by combining protein tags with polarity-sensitive fluorescent probes, which provide information about local nanoscale environments of target proteins within the subcellular compartments (organelles). Here, we designed three fluorescent probes based on solvatochromic nile red dye, conjugated to a HaloTag reactive targeting group through polyethylene glycol linkers of varying lengths. The probe with medium linker length, NR12-Halo, was found to label specifically a large variety of proteins localized in defined cell compartments, such as plasma membranes (outer and inner leaflets), endoplasmic reticulum, Golgi apparatus, cytosol, microtubules, actin, and chromatin. Owing to its polarity-sensitive fluorophore, the probe clearly distinguished the proteins localized within apolar lipid membranes from other proteins. Moreover, it revealed dramatic changes in the environment during the life cycle of proteins from biosynthesis to their expected localization and, finally, to recycling inside lysosomes. Heterogeneity in the local polarity of some membrane proteins also suggested a formation of low-polar protein aggregates, for example, within cell-cell contacts. The approach also showed that mechanical stress (cell shrinking by osmotic shock) induced a general polarity decrease in membrane proteins, probably due to the condensation of biomolecules. Finally, the nanoenvironment of some membrane proteins was affected by a polyunsaturated fatty acid diet, which provided the bridge between organization of lipids and proteins. The developed solvatochromic HaloTag probe constitutes a promising tool for probing nanoscale environments of proteins and their interactions within subcellular structures.

SARS-CoV-2 testing, infection and places of contamination in France, a national cross-sectional study, December 2021

BACKGROUND

This study aimed to describe the use of diagnostic testing for SARS-CoV-2 in France until December 2021, the characteristics of people infected, and places of contamination.

METHODS

Data were collected from the national 2021 Health Barometer cross-sectional study, which was conducted between February and December 2021 and included French-speaking individuals aged 18-85 years old selected through randomly generated landline and mobile phone numbers. Participants were interviewed about COVID-19-like symptoms in the previous 12 months, diagnostic testing for SARS-CoV-2, positive diagnosis for SARS-CoV-2, and the place(s) of contamination. Determinants of diagnostic testing and of infection were studied using univariate and multivariate Poisson regressions.

RESULTS

A total of 24,514 persons participated in the study. We estimated that 66.4% [65.0-67.7] of persons had been tested for SARS-CoV-2 the last time they experienced COVID-19-like symptoms, and that 9.8% [9.3-10.3] of the population in France - with or without symptoms - had been tested positive. Diagnostic testing was less frequent in men, unemployed persons, and people living alone; it was also less frequent during the first months of the pandemic. The estimated proportion of the population infected was higher in healthcare professionals (PRa: 1.5 [1.3-1.7]), those living in large cities ( > = 200 000 inhabitants, and Paris area) (1.4 [1.2-1.6]), and in households comprising > 3 persons (1.7 [1.5-2.0]). It was lower in retired persons (0.8 [0.6-0.97]) and those over 65 years old (0.6 [0.4-0.9]). Almost two-thirds (65.7%) of infected persons declared they knew where they were contaminated; 5.8% [4.5-7.4] reported being contaminated outdoors, 47.9% [44.8-51.0] in unventilated indoor environments, and 43.4% [40.3-46.6] in ventilated indoor environments. Specifically, 51.1% [48.0-54.2] declared they were contaminated at home or in a family of friend's house, 29.1% [26.4-31.9] at their workplace, 13.9% [11.9-16.1] in a healthcare structure, and 9.0% [7.4-10.8] in a public eating place (e.g., cafeteria, bar, restaurant).

CONCLUSIONS

To limit viral spread, preventive actions should preferentially target persons tested least frequently and those at a higher risk of infection. They should also target contamination in households, healthcare structures, and public eating places. Importantly, contamination is most frequent in places where prevention measures are most difficult to implement.

Acceptability of mandatory vaccination against influenza, measles, pertussis and varicella by workers in healthcare facilities: a national cross-sectional study, France, 2019

BACKGROUND

Vaccination of healthcare workers (HCW) aims to protect them and to reduce transmission to susceptible patients. Influenza, measles, pertussis, and varicella vaccinations are recommended but not mandatory for HCW in France. Insufficient vaccine coverage for these diseases in HCW has raised the question of introducing mandatory vaccination. We conducted a survey to estimate acceptability of mandatory vaccination for these four vaccines by HCW working in healthcare facilities (HCF) in France, and to identify associated determinants.

METHODS

In 2019, we performed a cross-sectional survey of physicians, nurses, midwives and nursing assistants working in HCF in France using a randomised stratified three-stage sampling design (HCF type, ward category, HCW category). Data were collected in face-to-face interviews using a tablet computer. We investigated the possible determinants of acceptability of mandatory vaccination using univariate and multivariate Poisson regressions, and estimated prevalence ratios (PR).

RESULTS

A total of 8594 HCW in 167 HCF were included. For measles, pertussis, and varicella, self-reported acceptability of mandatory vaccination (very or quite favourable) was 73.1% [CI95%: 70.9-75.1], 72.1% [69.8-74.3], and 57.5% [54.5-57.7], respectively. Acceptability varied according to i) HCW and ward category for these three vaccinations, ii) age group for measles and pertussis, and iii) sex for varicella. For mandatory influenza vaccination, acceptability was lower (42.7% [40.6-44.9]), and varied greatly between HCW categories (from 77.2% for physicians to 32.0% for nursing assistants).

CONCLUSION

HCW acceptability of mandatory vaccination was high for measles, pertussis and varicella but not as high for influenza. Vaccination for COVID-19 is mandatory for HCW in France. Replication of this study after the end of the COVID-19 crisis would help assess whether the pandemic had an impact on their acceptability of mandatory vaccination, in particular for influenza.

PSL Chemical Biology Symposia Third Edition: A Branch of Science in its Explosive Phase

This symposium is the third PSL (Paris Sciences & Lettres) Chemical Biology meeting (2016, 2019, 2023) held at Institut Curie. This initiative originally started at Institut de Chimie des Substances Naturelles (ICSN) in Gif-sur-Yvette (2013, 2014), under the directorship of Professor Max Malacria, with a strong focus on chemistry. It was then continued at the Institut Curie (2015) covering a larger scope, before becoming the official PSL Chemical Biology meeting. This latest edition was postponed twice for the reasons that we know. This has given us the opportunity to invite additional speakers of great standing. This year, Institut Curie hosted around 300 participants, including 220 on site and over 80 online. The pandemic has had, at least, the virtue of promoting online meetings, which we came to realize is not perfect but has its own merits. In particular, it enables those with restricted time and resources to take part in events and meetings, which can now accommodate unlimited participants. We apologize to all those who could not attend in person this time due to space limitation at Institut Curie.

Aldolase and N-Heterocyclic Carbene Gold(I) Catalysts: Compartmentalization and Immobilization on anionic clays for Concurrent Hybrid Catalysis at acidic pH

One of the last limitation to concurrent reactions involving hybrid catalysis is pH. This has been solved by mixing a catalyst, operating at acidic pH, and an aldolase, through enzyme...

Fluorescence-Activating and Absorption-Shifting Tags for Advanced Imaging and Biosensing

Fluorescent labels and biosensors play central roles in biological and medical research. Targeted to specific biomolecules or cells, they allow noninvasive imaging of the machinery that govern cells and organisms in real time. Recently, chemogenetic reporters made of organic dyes specifically anchored to genetic tags have challenged the paradigm of fully genetically encoded fluorescent proteins. Combining the advantage of synthetic fluorophores with the targeting selectivity of genetically encoded tags, these chemogenetic reporters open new exciting prospects for studying cell biochemistry and biology. In this Account, we present the growing toolbox of fluorescence-activating and absorption-shifting tags (FASTs), small monomeric proteins of 14 kDa (125 amino acids residues) that can be used as markers to monitor gene expression and protein localization in live cells and organisms. Engineered by directed protein evolution from the photoactive yellow protein (PYP) from the bacterium Halorhodospira halophila, prototypical FAST binds and stabilizes the fluorescent state of live-cell compatible hydroxybenzylidene rhodanine chromophores. This class of chromophores are normally dark when free in solution or in cells because they dissipate light energy through nonradiative processes. The protein cavity of FAST allows the stabilization of the deprotonated state of the chromophore and blocks the chromophore into a planar conformation, which leads to highly fluorescent protein-chromophore assemblies. The use of such fluorogenic dyes (also called fluorogens) enables the imaging of FAST fusion proteins in cells with high contrast without the need to remove unbound ligands through separate washing steps. Fluorogens with various spectral properties exist nowadays allowing investigators to adjust the spectral properties of FAST to their experimental conditions. Molecular engineering allowed furthermore to generate membrane-impermeant fluorogens for the selective labeling of cell-surface proteins. Over the years, we generated a collection of FAST variants with expanded spectral properties or fluorogen selectivity using a concerted strategy involving molecular engineering and directed protein evolution. Moreover, protein engineering allowed us to adapt FASTs for the design of fluorescent biosensors. Circular permutation enabled the generation of FAST variants with increased conformational flexibility for the design of biosensors in which fluorogen binding is conditioned to the recognition of a given analyte. Bisection of FASTs into two complementary fragments allowed us furthermore to create split variants with reversible complementation that allow the detection and imaging of dynamic protein-protein interactions. We provide, here, a general overview of the current state of development of these different systems and their applications for advanced live cell imaging and biosensing and discuss potential future directions.

New Zealand experience with implementation of the ESO-ESMO consensus guidelines for advanced breast cancer-report of achievements and lessons learned

BACKGROUND

People with advanced breast cancer (ABC) in New Zealand (NZ) have a poorer five-year survival than their peers in other developed countries. Comparisons of ABC care in NZ with other countries suggest that NZ is sometimes out of line with international standards and that inequities exist within the NZ healthcare system. Our aim was to develop nationwide consensus guidelines for diagnosis and treatment of ABC that are uniquely suited for the NZ context and can be applied across the nation. We describe the process of creating, voting on, and disseminating the guidelines, and provide insight into how we can better optimize these processes for the NZ context in the future.

METHODS

The ABC5 ESO-ESMO consensus guidelines were used and adapted to the NZ clinical context. A panel of breast cancer clinicians voted on these guidelines using the same model of membership representation as ABC5.

OUTCOME

Overall consensus was equally high between ABC5 and ABC-NZ. Four NZ specific guidelines were introduced. The European-style panel discussion needs some adaptations for the NZ situation and a wider and more thorough consultation process, before voting begins, is preferred. The NZ Breast Special Interest Group has endorsed and agreed to take ownership of these and future guidelines and to facilitate the next iteration of the ABC-NZ guidelines meeting.

CONCLUSIONS

The process was successful in creating the guidelines but can be improved in future meetings to streamline the process of creating and updating guidelines in the manner most suited to the NZ context and audience.

Influenza vaccination coverage of professionals working in nursing homes in France and related determinants, 2018-2019 season: a cross-sectional survey

BACKGROUND

The burden of influenza morbidity and mortality in nursing homes (NH) is high. Vaccination of residents and professionals working in NH is the main prevention strategy. Despite recommendations, vaccination coverage among professionals is generally low.

METHODS

We performed a nationwide cross-sectional survey of NH using a single-stage stratified random sampling design to estimate influenza vaccination coverage in NH healthcare workers (HCW) and non-medical professionals in France during the 2018-2019 season, and to identify measures likely to increase it. For each NH, a questionnaire was completed with aggregated data by one member of the management team. A multivariate analysis was performed using a negative binomial regression.

RESULTS

Five-hundred and eighty nine NH filled in the study questionnaire (response rate: 49.5%). When considering all professionals (i.e., HCW and non-medical professionals), overall vaccination coverage was 30.6% (95%CI [28.2-33.0], range: 1.6-96.2). Overall influenza vaccination coverage in HCW was 31.9% [29.7-34.1]. It varied according to occupational category: 75.5% [69.3-81.7] for physicians, 42.9% [39.4-46.4] for nurses, 26.7% [24.5-29.0] for nursing assistants, and 34.0% [30.1-38.0] for other paramedical personnel. Vaccination coverage was higher i) in private nursing homes (RRa: 1.3, [1.1-1.5]), ii) in small nursing homes (0.9 [0.8-0.9]), iii) when vaccination was offered free of charge (1.4, [1.1-1.8]), iv) when vaccination promotion for professionals included individual (1.6 [1.1-2.1]) or collective (1.3 [1.1-1.5]) information sessions, videos or games (1.4 [1.2-1.6], v) when information on influenza vaccines was provided (1.2 [1.0-1.3], and finally, vi) when a vaccination point of contact-defined as an HCW who could provide reliable information on vaccination-was nominated within the nursing home (1.7 [1.3-2.2]).

CONCLUSIONS

Urgent and innovative actions are required to increase coverage in HCW. Vaccination programmes should include free on-site vaccination and education campaigns, and particularly target nursing assistants. The results of this nationwide study provide keys for improving influenza vaccination coverage in HCW. Programmes should ensure that information on influenza vaccines is provided by a vaccination point of contact in NH using attractive media. Combining the different prevention measures proposed could increase coverage in NH nationwide by over 50%.

An expanded palette of fluorogenic HaloTag probes with enhanced contrast for targeted cellular imaging

We report the development of HaloTag fluorogens based on dipolar flexible molecular rotor structures. By modulating the electron donating and withdrawing groups, we have tuned the absorption and emission wavelengths to design a palette of fluorogens with emissions spanning the green to red range, opening new possibilities for multicolor imaging. The probes were studied in glycerol and in the presence of HaloTag and exhibited good fluorogenic properties thanks to a viscosity-sensitive emission. In live-cell confocal imaging, the fluorogens yielded only a very low non-specific signal that enabled wash-free targeted imaging of intracellular organelles and proteins with good contrast. Combining experimental studies and theoretical investigation of the protein/fluorogen complexes by molecular dynamics, these results offer new insight into the design of molecular rotor-based fluorogenic HaloTag probes in order to improve reaction rates and the imaging contrast.

Arylopeptoid oligomers functionalised by combinatorial or sequential on-resin click chemistry using a copper(I)-N-heterocyclic carbene catalyst

An efficient on-resin click chemistry protocol using a stable copper(I)-N-heterocyclic carbene catalyst is developed for post-functionalization of N-alkylated aminomethylbenzamide oligomers (arylopeptoids). The accessibility to a panel of polyfunctionalized N-substituted aromatic oligoamides by solid-phase synthesis is demonstrated using combinatorial and sequential approaches.

Isolating and Engineering Fluorescence-Activating Proteins Using Yeast Surface Display

This protocol describes the workflow to isolate and engineer fluorescence-activating proteins by yeast surface display. Fluorescence-activating proteins are an emerging class of fluorescent chemogenetic reporters for monitoring gene expression and protein localization in living cells and organisms. They become fluorescent upon binding exogenously applied fluorogenic organic dyes. Efficient fluorescence-activating proteins can be selected from yeast-displayed libraries by iterative rounds of fluorescence-activated cell sorting. The overall strategy is described, as well as a strategy for characterizing the affinity and spectroscopic properties of the selected clones.

Engineering of a fluorescent chemogenetic reporter with tunable color for advanced live-cell imaging

Biocompatible fluorescent reporters with spectral properties spanning the entire visible spectrum are indispensable tools for imaging the biochemistry of living cells and organisms in real time. Here, we report the engineering of a fluorescent chemogenetic reporter with tunable optical and spectral properties. A collection of fluorogenic chromophores with various electronic properties enables to generate bimolecular fluorescent assemblies that cover the visible spectrum from blue to red using a single protein tag engineered and optimized by directed evolution and rational design. The ability to tune the fluorescence color and properties through simple molecular modulation provides a broad experimental versatility for imaging proteins in live cells, including neurons, and in multicellular organisms, and opens avenues for optimizing Förster resonance energy transfer (FRET) biosensors in live cells. The ability to tune the spectral properties and fluorescence performance enables furthermore to match the specifications and requirements of advanced super-resolution imaging techniques.

The role of organization of care in GPs' prevention practice

BACKGROUND

General practitioners (GPs) do not systematically include preventive recommendations in their practice, and some characteristics of health care organization are associated with more systematic prevention. But the characteristics of health care organization may act in a nonuniform manner depending on the type of preventive care. Thus, one characteristic can be positively associated with one type of preventive care and negatively associated with another. Our aim was to investigate the association between health care organization in general practice and different areas of preventive care (immunization and addiction prevention), in search of nonuniform associations.

METHODS

We used a representative survey of 1,813 French GPs conducted in 2009. Four preventive care practices were studied: immunization through flu and HPV vaccination, and prevention of addictive behaviors concerning tobacco and alcohol use.Characteristics of GPs' health care organization and the social context of their practice were collected (spatial accessibility to GPs and socioeconomic level of the area of practice). We constructed mixed models to study associations and interactions between the organization variables and preventive care.

RESULTS

Four out of five characteristics of GPs' organization have uneven impacts on different types of preventive care (p-interaction < 10-4). For example, number of daily consultations is associated with better immunization prevention but with poorer prevention counseling in addictive behaviors. In contrast, working with digital medical files is uniformly associated with both types of preventive care (OR = 1.29 [1.15-1.45]; P < 10-4).

CONCLUSION

An approach centered on specific types of preventive care should help deepen our understanding of prevention and possibly help to identify a new typology for preventive care.

Increased awareness and knowledge of Lyme Borreliosis and tick bite prevention among the general population in France: 2016 and 2019 health barometer survey

Background

Lyme borreliosis (LB) is the most frequent tick-borne disease in France. In the absence of a vaccine, LB prevention mainly relies on reducing tick bites. In 2016, the French Ministry of Health launched a national plan against tick-borne infections, including a prevention component. To evaluate the impact of this prevention strategy, we assessed knowledge and practices of tick bite prevention using the 2016 and 2019 national surveys on health attitudes and beliefs known as the French Health Barometer.

Methods

The Health Barometer is a repeated nationwide phone survey conducted annually on a random sample aged 18 to 75 years living in mainland France. In 2016 and 2019, participants were asked, among others, about their exposure to ticks, their behavior and practices regarding tick bites, and their knowledge about LB and its prevention.

Results

In 2019, 30% of the population reported a lifetime tick bite and 6% in the last year, an increase from 25% and 4%, respectively, in 2016 (p < 0.001). In 2019, 25% of the population felt exposed to tick bites compared to 23% in 2016 (p < 0.001). The proportion of participants who had heard about LB and who considered themselves well informed respectively increased from 66% and 29% in 2016 to 79% and 41% in 2019, (p < 0.001). In 2019 compared to 2016, a greater part of the French population applied protective measures against tick bites, particularly wearing protective clothing (74% vs 66%, p < 0.001) and regular tick checks and prompt tick removal after exposure (54% vs 47%, p < 0.001).

Conclusions

A substantial proportion of French residents are exposed to tick bites and apply protective measures. Our findings indicate a trend toward an increased knowledge and awareness of tick bites and LB between 2016 and 2019 in France. Our results can be used to target future information campaigns to specific age groups or at-risk areas in addition to the general population. However, we need to further study the barriers to the use of preventive measures.

Versatile On-Demand Fluorescent Labeling of Fusion Proteins Using Fluorescence-Activating and Absorption-Shifting Tag (FAST)

Observing the localization, the concentration, and the distribution of proteins in cells or organisms is essential to understand theirs functions. General and versatile methods allowing multiplexed imaging of proteins under a large variety of experimental conditions are thus essential for deciphering the inner workings of cells and organisms. Here, we present a general method based on the non-covalent labeling of a small protein tag, named FAST (fluorescence-activating and absorption-shifting tag), with various fluorogenic ligands that light up upon labeling, which makes the simple, robust, and versatile on-demand labeling of fusion proteins in a wide range of experimental systems possible.

N-Alkylated Aromatic Poly- and Oligoamides

N-alkylated aromatic poly- and oligoamides are a particular class of abiotic foldamers that is deprived of the capability of forming intramolecular hydrogen-bonding networks to stabilize their tri-dimensional structure. The alkylation of the backbone amide nitrogen atoms greatly increases the chemical diversity accessible for aromatic poly- and oligoamides. However, the nature and the conformational preferences of the N,N-disubstituted amides profoundly modify the folding properties of these aromatic poly- and oligoamides. In this Review, representative members of this class of aromatic poly- and oligoamides will be highlighted, among them N-alkylated phenylene terephthalamides, benzanilides, pyridylamides, and aminomethyl benzamide oligomers. The principal synthetic pathways to the main classes of N-alkylated aromatic polyamides with narrow to broad molecular-weight distribution, or oligoamides with specific sequences, will be detailed and their foldameric properties will be discussed. The Review will end by describing the few applications reported to date and future prospects for the field.

Myocardial infarction rates overview during COVID-19 pandemic In France: Results of the MODIF registry

Background

The emergence of Coronavirus disease 2019 (COVID-19) has evolved into a global pandemic. Systems of care have been reorganized worldwide in an effort to preserve hospital bed capacity. In France, from March 17 to May 11 2020, government imposed a complete lockdown on the whole population. Only urgent cardiac procedures have been ensured such as ST-elevation myocardial infarction (STEMI) revascularization. Some previously published studies suggest a reduction of admission for STEMI in many countries. Nevertheless, strong evidences and data across different French regions that have been affected variously by the outbreak are still lacking.

Purpose

We aimed to describe the incidence rates and characteristics of patients presenting with STEMI in order to evaluate the impact of the COVID-19 outbreak on STEMI care in France covering the lockdown period compared to same period one year ago.

Methods

We performed a retrospective multicenter registry across 60 French interventional cardiology centers including all consecutive STEMI patients referred for urgent revascularization in the heart catheterization laboratory between two periods: March 1^st to May 31th 2020 compared with March 1^st to May 31th 2019. Comprehensive data, including clinical, biological, COVID status and angiographic variables including time taken for care were recorded at admission. The primary outcome was a composite of invasive mechanical ventilation support or in-hospital death. The secondary outcome was the occurrence of myocardial infarction related complications during hospitalization. Enrollement is not complete at the time of the abstract submission.

Conclusion

This data collection between two periods with and without COVID19 will gave insights for a complete descriptive cartography of STEMI patients among different French regions which have been variously impacted by the outbreak.

CCS patients with polyvascular disease are a high risk but heterogenous subset of patients: insights from the CLARIFY registry

Introduction

Polyvascular disease constitutes a powerful predictor of cardiovascular events, is found in 10 to 15% of chronic coronary syndromes (CCS) patient. Smoking and diabetes mellitus are strongly associated with polyvascular disease. Risk stratification is key to select the most appropriate therapeutic strategy for a given patient.

Purpose

We aimed to describe 5-year ischaemic risk of CCS patients according to vascular disease phenotype and diabetic or smoking status.

Method

We analyzed data from 32 703 consecutive CCS outpatients (45 countries) enrolled between November 2009 to June 2010 in the prospective observational CLARIFY registry. Three mutually exclusive groups were compared: Coronary artery disease (CAD) alone, CAD with peripheral artery disease (PAD) or cerebrovascular disease (CVD) (CAD+1), CAD with CVD and PAD (CAD+2). Primary outcome was a composite of cardiovascular death, myocardial infarction or stroke, adjusted on age, sex and geographic origin at 5 years.

Results

At baseline, 26440 (80.8%) patients were diagnosed with CAD alone, 4967 (15.2%) had CAD+1, 1296 (4%) had CAD+2. Overall, 9501 (29%) patients were diabetics, 19184 (58.7%) were smokers or ex-smokers and only 9220 (28.2%) were free of these two major cardiovascular risk factors. Primary outcome increasing gradually according to the number of arterial diseases locations from 8.4% (95% CI 8.09–8.73) in patients with CAD alone to 17.4% (95% CI 16.95–17.83) of CAD+2 patients (p&lt;0.001). Subgroup analysis according to diabetes or smoking status further enriched risk stratification from 7% (95% CI 6.48–7.59) in non-diabetic, non-smoking CAD alone patients to 20.3% (95% CI 19.08–21.44) in diabetics and smokers CAD+ 2 patients (Figure 1). Diabetic CAD alone patients had a comparable risk to that of non-diabetic and non-smoking polyvascular patients, 9.8% (95% CI 8.82–10.68) vs 10.3% (95% CI 9.61–10.96), p=0.38. Outcome was similar between polyvascular diabetic patients, regardless of the number of arterial diseases, 15.5% (95% CI 14.31–16.60) for CAD+1 and 15.0 (95% CI 13.88–16.13) for CAD+2, p=0.83. Smoking increased 5-year risk proportionally to the number of symptomatic arterial bed, 8.2% (95% CI 7.72–8.68) vs 11.8% (95% CI 11.18–12.31) vs 17.9% (95% CI 17.18–18.54), respectively for CAD alone, CAD+1 and CAD+2.

Conclusion

CCS patients with polyvascular disease remain at high risk of ischaemic events in the contemporary practice with widespread secondary prevention therapies. Polyvascular is a very heterogenous subset of patients with ischaemic risk varying not only according to the number of vascular bed diseased but also according to smoking and diabetes status, two conditions present in the vast majority of CCS patients. Diabetes confers upfront a maximal increased risk. Identification of higher risk subsets in polyvascular patients can potentially identify those that could derived the greatest benefit from new secondary prevention strategies.

Figure 1

Funding Acknowledgement

Type of funding source: Public hospital(s). Main funding source(s): Assistance Publique-Hôpitaux de Paris

Fluorescent secreted bacterial effectors reveal active intravacuolar proliferation of Listeria monocytogenes in epithelial cells

Real-time imaging of bacterial virulence factor dynamics is hampered by the limited number of fluorescent tools suitable for tagging secreted effectors. Here, we demonstrated that the fluorogenic reporter FAST could be used to tag secreted proteins, and we implemented it to monitor infection dynamics in epithelial cells exposed to the human pathogen Listeria monocytogenes (Lm). By tracking individual FAST-labelled vacuoles after Lm internalisation into cells, we unveiled the heterogeneity of residence time inside entry vacuoles. Although half of the bacterial population escaped within 13 minutes after entry, 12% of bacteria remained entrapped over an hour inside long term vacuoles, and sometimes much longer, regardless of the secretion of the pore-forming toxin listeriolysin O (LLO). We imaged LLO-FAST in these long-term vacuoles, and showed that LLO enabled Lm to proliferate inside these compartments, reminiscent of what had been previously observed for Spacious Listeria-containing phagosomes (SLAPs). Unexpectedly, inside epithelial SLAP-like vacuoles (eSLAPs), Lm proliferated as fast as in the host cytosol. eSLAPs thus constitute an alternative replication niche in epithelial cells that might promote the colonization of host tissues.

Bacterial pathogens secrete virulence factors to subvert their hosts; however, monitoring bacterial secretion in real-time remains challenging. Here, we developed a convenient method that enabled fluorescent imaging of secreted proteins in live microscopy, and applied it to the human pathogen Listeria monocytogenes. Listeria has been described to invade cells and proliferate in their cytosol; it is first internalized inside vacuoles, from where it escapes thanks to the secretion of virulence factors that disrupt membranes. Our work revealed the existence, in human epithelial cells, of a population of Listeria that failed to escape vacuoles but instead multiplied efficiently therein, despite—and in fact, thanks to—the active secretion of a toxin that permeates membranes. This intravacuolar niche may provide Listeria with an alternative strategy to colonize its host.

Visualizing the dynamics of exported bacterial proteins with the chemogenetic fluorescent reporter FAST

Bacterial proteins exported to the cell surface play key cellular functions. However, despite the interest to study the localisation of surface proteins such as adhesins, transporters or hydrolases, monitoring their dynamics in live imaging remains challenging, due to the limited availability of fluorescent probes remaining functional after secretion. In this work, we used the Escherichia coli intimin and the Listeria monocytogenes InlB invasin as surface exposed scaffolds fused with the recently developed chemogenetic fluorescent reporter protein FAST. Using both membrane permeant (HBR-3,5DM) and non-permeant (HBRAA-3E) fluorogens that fluoresce upon binding to FAST, we demonstrated that fully functional FAST can be exposed at the cell surface and used to specifically tag the external side of the bacterial envelop in both diderm and monoderm bacteria. Our work opens new avenues to study the organization and dynamics of the bacterial cell surface proteins.

Orthogonal fluorescent chemogenetic reporters for multicolor imaging

Spectrally separated fluorophores allow the observation of multiple targets simultaneously inside living cells, leading to a deeper understanding of the molecular interplay that regulates cell function and fate. Chemogenetic systems combining a tag and a synthetic fluorophore provide certain advantages over fluorescent proteins since there is no requirement for chromophore maturation. Here, we present the engineering of a set of spectrally orthogonal fluorogen activating tags based on the Fluorescence Activating and absorption Shifting Tag (FAST), that are compatible with two-color, live cell imaging. The resulting tags, greenFAST and redFAST, demonstrate orthogonality not only in their fluorogen recognition capabilities, but also in their one- and two-photon absorption profiles. This pair of orthogonal tags allowed the creation of a two-color cell cycle sensor capable of detecting very short, early cell cycles in zebrafish development, and the development of split complementation systems capable of detecting multiple protein-protein interactions by live cell fluorescence microscopy.

Illuminating Cellular Biochemistry: Fluorogenic Chemogenetic Biosensors for Biological Imaging

Cellular activity is defined by the precise spatiotemporal regulation of various components, such as ions, small molecules, or proteins. Studying cell physiology consequently requires the optical recording of these processes, notably by using fluorescent biosensors. The recent development of various fluorogenic systems greatly expanded the palette of reporters to be included in these sensors design. Fluorogenic reporters consist of a protein or RNA tag that can complex either an endogenous or a synthetic fluorogenic dye (so-called fluorogen). The intrinsic nature of these tags, along with the high tunability of their cognate chromophore provide interesting features such as far-red to near-infrared emission, oxygen independence, or unprecedented color versatility. These engineered photoreceptors, self-labelling proteins, or noncovalent aptamers and protein tags were rapidly identified as promising reporters to observe biological events. This Minireview focuses on the new perspectives they offer to design unique and innovative biosensors, thus pushing the boundaries of cellular imaging.

Sensing cellular biochemistry with fluorescent chemical-genetic hybrids

Fluorescent biosensors are powerful tools for the detection of biochemical events inside cells with high spatiotemporal resolution. Biosensors based on fluorescent proteins often suffer from issues with photostability and brightness. On the other hand, hybrid, chemical-genetic systems present unique opportunities to combine the strengths of synthetic, organic chemistry with biological macromolecules to generate exquisitely tailored semisynthetic sensors.

A polycarboxylic chelating ligand for efficient resin purification of His-tagged proteins expressed in mammalian systems

We describe the synthesis of a novel polyamino polycarboxylic ligand, its ability to coordinate metal-ions and attachment to a solid support designed for protein purification through Immobilised Metal-ion Affinity Chromatography (IMAC). The resin was found to be highly efficient for purification of His-tagged HCV E2 glycoproteins expressed in 293T mammalian cells.

Proteomics of transforming growth factor β1 (TGF β1) signaling in 184A1 human breast epithelial cells suggests the involvement of casein kinase 2α in TGF β1-dependent p53 phosphorylation at Ser392

AIM

Transforming growth factor β1 (TGF β1) is a potent regulator of breast tumorigenesis. It inhibits proliferation of carcinoma cells, but the strength of its inhibitory action varies for cells from benigh, non-metastatic or metastatic tumors. The aim of this work was to generate a proteome profile of TGF β1 action on non-tumorigenic human breast epithelial cells 184A1, and validate predicted involvement of casein kinase 2α (CK2α), p53 and structure-specific recognition protein-1 (SSRP1).

MATERIALS AND METHODS

Two-dimensional gel electrophoresis and mass spectrometry were used to identify TGF β1-regulated proteins in 184A1 human breast immortalized non-tumorigenic cells. 184A1 cells may serve as a model of benign breast neoplasia. These cells were obtained from normal mammary tissue, were immortalized but are not malignant, and were obtained from the American Type Culture Collection. The systemic analysis was performed by using the Cytoscape tool. Transfection of cells with CK2α construct and small interfering RNAs to CK2α and SSRP1 were used to assess an impact of CK2α and SSRP1 on phosphorylation of the p53 and cell proliferation.

RESULTS

Proliferation of 184A1 cells was transiently inhibited by TGF β1. We identified 100 and 47 unique proteins which changed their expression and/or ³⁵S-incorporation, respectively, upon treatment with TGF β1 for 2 h, 8 h or 24 h. Cell proliferation, death, migration, and metabolism were among the biological regulatory processes retrieved by the network analysis as affected by the identified proteins. The network analysis suggested that TGF β1 may affect the phosphorylation of p53 at Ser392 by engaging CK2α. This was confirmed by the immunoblotting and cell proliferation assays.

CONCLUSION

We report here the list of 147 TGF β1-regulated proteins in immortalized non-tumorigenic human breast epithelial cells, and show involvement of CK2α in the regulation of p53 Ser392 phosphorylation.

We've Come a Long Way, Baby: Announcing a Special Issue to Commemorate the Publication of Molecule's 20,000th Paper

On behalf of my Section Editor-in-Chief co-author colleagues I am pleased to announce a Special Issue to commemorate the recent publication of Molecules' 20,000th paper [...].

Next-Generation Fluorogen-Based Reporters and Biosensors for Advanced Bioimaging

Our ability to observe biochemical events with high spatial and temporal resolution is essential for understanding the functioning of living systems. Intrinsically fluorescent proteins such as the green fluorescent protein (GFP) have revolutionized the way biologists study cells and organisms. The fluorescence toolbox has been recently extended with new fluorescent reporters composed of a genetically encoded tag that binds endogenously present or exogenously applied fluorogenic chromophores (so-called fluorogens) and activates their fluorescence. This review presents the toolbox of fluorogen-based reporters and biosensors available to biologists. Various applications are detailed to illustrate the possible uses and opportunities offered by this new generation of fluorescent probes and sensors for advanced bioimaging.

HCV and HBV prevalence based on home blood self-sampling and screening history in the general population in 2016: contribution to the new French screening strategy

Background

The advent of effective direct-acting antivirals (DAAs), has prompted an assessment of the French Hepatitis C virus (HCV) screening strategy, which historically targeted high-risk groups. One of the options put forward is the implementation of combined (i.e., simultaneous) HCV, Hepatitis B virus (HBV) and HIV screening for all adults at least once during their lifetime (“universal combined screening”). However, recent national survey-based data are lacking to guide decision-making regarding which new strategy to implement. Accordingly, we aimed to provide updated data for both chronic hepatitis C (CHC) and B (CHB) prevalence and for HCV and HBV screening history, using data from the BaroTest and 2016 Health Barometer (2016-HB) studies, respectively.

Methods

2016-HB was a national cross-sectional phone based health survey conducted in 2016 among 20,032 randomly selected individuals from the general population in mainland France. BaroTest was a virological sub-study nested in 2016-HB. Data collected for BaroTest were based on home blood self-sampling on dried blood spots (DBS).

Results

From 6945 analyzed DBS, chronic hepatitis C (CHC) and B (CHB) prevalence was estimated at 0.30% (95% Confidence Interval (CI): 0.13-0.70) and 0.30% (95% CI: 0.13-0.70), respectively. The proportion of individuals aware of their status was estimated at 80.6% (95% CI: 44.2-95.6) for CHC and 17.5% (95% CI: 4.9-46.4) for CHB. Universal combined screening would involve testing between 32.6 and 85.3% of 15-75 year olds according to whether we consider only individuals not previously tested for any of the three viruses, or also those already tested for one or two of the viruses.

Conclusions

Our data are essential to guide decision-making regarding which new HCV screening recommendation to implement in France. They also highlight that efforts are still needed to achieve the WHO’s targets for eliminating these diseases. Home blood self-sampling may prove to be a useful tool for screening and epidemiological studies.